This invention relates to an improved trench shoring box unit. More particularly, it relates to a lightweight trench shoring unit that can readily be adapted to shore up the walls of trenches having a variety of dimensions.
A prior art trench shoring box unit is disclosed in German Patent Application No. 25 02 567, where the walls consist of a pair of steel plates facing each other and are connected together by U-section spacers. The legs of the U-section spacers are spot welded to the plates. Not only is this kind of trench shoring box unit heavy and bulky to handle, but it is costly to manufacture.